Adjustable anchor systems and methods

ABSTRACT

An adjustable anchor system provides for securing tissue to bone and includes an anchor with a collapsible suture loop affixed thereto and a tissue suture connected to the collapsible suture loop. After the tissue suture is loaded into the tissue and the anchor implanted into the bone the collapsible loop is collapsed to tension the tissue suture.

This application is a continuation of U.S. patent application Ser. No.14/754,773, filed on Jun. 30, 2015, and entitled “Adjustable AnchorSystems and Methods,” which is a divisional of U.S. patent applicationSer. No. 13/336,151, filed on Dec. 23, 2011, entitled “Adjustable AnchorSystems and Methods,” and which issued as U.S. Pat. No. 9,095,331 onAug. 4, 2015, which is a continuation-in-part of U.S. patent applicationSer. No. 12/977,146, filed on Dec. 23, 2010, entitled “Adjustable AnchorSystems and Methods,” and which issued as U.S. Pat. No. 8,821,543 onSep. 2, 2014, each of which is hereby incorporated by reference in itsentirety.

BACKGROUND Field

The invention relates to a system and method for securing tissue to boneand more particularly to adjustable tensioning of tissue whicheliminates the need for knot-tying by a user.

Description of the Related Art

A common injury, especially among athletes, is the complete or partialdetachment of tendons, ligaments or other soft tissues from bone. Tissuedetachment may occur during a fall, by overexertion, or for a variety ofother reasons. Surgical intervention is often needed, particularly whentissue is completely detached from its associated bone. Currentlyavailable devices for tissue attachment include screws, staples, sutureanchors and tacks. An example of a cannulated suture anchor is providedin U.S. Patent Application Publication No. 2008/0147063 by Cauldwell etal.

There are a number of suture implant systems which proclaim to be“knotless”, that is, to not require a surgeon to tie a knot duringsurgery. Many such systems control tension on tissue by the depth towhich an anchor is driven into bone. U.S. Pat. Nos. 5,782,864 and7,381,213 by Lizardi disclose certain types of suture anchors whichcapture a fixed-length loop of suture. Adjustable loop knotless anchorassemblies utilizing an anchor element inserted into a sleeve aredescribed by Thal in U.S. Pat. Nos. 5,569,306 and 6,045,574 and in U.S.Patent Application Publication No. 2009/0138042.

Suture anchor systems with sliding knots for repairing torn or damagedtissue, especially for meniscal repair, are disclosed in U.S. Pat. No.7,390,332 by Selvitelli et al. and are utilized in the OmniSpan™meniscal repair system commercially available from DePuy Mitek Inc., 325Paramount Drive, Raynham, Mass. 02767. Other suture anchor systems withsliding and locking knots for repairing tissue include U.S. Pat. No.6,767,037 by Wenstrom, Jr.

It is therefore desirable to adjust tension on a tissue after an anchorhas been fixated in bone without requiring a surgeon to tie any knots,especially during arthroscopic procedures.

SUMMARY

A suture anchor system according to the present invention comprises asuture anchor, a collapsible suture loop affixed to the anchor and atissue suture attached to the collapsible suture loop.

In one aspect of the invention, the tissue suture is looped through thecollapsible loop. The tissue suture can be formed from a separate pieceof suture than the collapsible loop or from the same piece of suturefrom which is formed the collapsible loop. In one aspect of theinvention, the tissue suture has a characteristic selected from the listof: materials, construction, size, and coatings which differs from suchsame characteristic of the collapsible loop. For instance the tissuesuture can be adapted to be gentle to the tissue and the collapsibleloop could be formed from a suture which slides more easily, has highstrength, cinches well into a knot or other such characteristic which isnot as important to the tissue suture. Preferably, the collapsiblesuture loop has a lower coefficient of friction than the tissue suture.

Preferably, the collapsible suture loop comprises a sliding knot throughwhich a portion of the suture loop may be drawn to collapse itself.Preferably, the sliding knot comprises a fixed tail and a post limb. Inaspect of the invention, the tissue suture comprises the fixed tail.

Preferably, an attachment member on the anchor passes through thecollapsible suture loop to affix the collapsible loop to the anchor.

Preferably, the anchor has a central axial cannulation, the collapsibleloop comprises a sliding knot which has a post limb extending from thesliding knot wherein tension upon the post limb collapses the loop andthe collapsible loop and the post limb extend proximally out of thecannulation. Preferably a post in the anchor passes through thecollapsible loop wherein to affix the collapsible loop to the anchor. Inone aspect of the invention, the sliding knot is disposed distal of thepost. Then, preferably, the post limb passes around a retaining surfaceadjacent to where the post passes through the collapsible loop and thenpasses proximally out of the cannulation. In such configuration thesliding knot is disposed proximal of the post. In another aspect of theinvention, the tissue suture comprises the fixed tail.

Preferably, bone engaging protrusions are provided about the sutureanchor. Preferably, the anchor has an elongated cylindrical shapewhereby to be fixedly received within a hole drilled into a bone. Alsopreferably, the suture anchor, collapsible loop and tissue suture aresterile and packaged in a bacteria proof enclosure, also preferably withinstructions for their use in attaching soft tissue to bone as describedherein.

In one aspect of the invention a suture receiver is provided on thesuture anchor for receiving the tissue suture. The suture receiver cancomprise an eyelet at a distal end of the suture anchor. The eyelet canbe formed of overlapping arms whereby to allow suture to be loaded intothe eyelet between the arms. Alternatively, the eyelet is formed of asidewall which has a funnel shaped slot therethrough to allow suture tobe loaded into the eyelet through the slot. The suture receiver cancomprise a notch at the distal end of the anchor, the notch beingseparate from the collapsible loop such that tissue suture in the notchdoes not abut any moving portion of the collapsible loop. The suturereceiver helps guide the tissue suture along an exterior of the sutureanchor as it is being implanted into a bone to trap the tissue suturebetween the anchor and the bone.

In one aspect of the invention, the anchor has a central axialcannulation and a suture grasper is received through the cannulationwhereby to facilitate threading the tissue suture through thecannulation after it is loaded into a soft tissue. The suture grasperpreferably comprises an elongated body passing through the cannulationwith a suture capture mechanism distal of the suture anchor. The suturecapture mechanism can be a loop of flexible material through which thetissue suture can be threaded.

A method according to the present invention provides for attaching asoft tissue to a bone. The method comprises the steps of: passing atissue suture through a piece of soft tissue; implanting the sutureanchor into the bone; and collapsing a collapsible suture loop that isaffixed to the anchor and connected to the tissue suture and therebytensioning the tissue suture. Preferably, slack in the tissue suture isremoved prior to the step of implanting the suture anchor into the bone.

In one aspect of the invention the method comprises the step of trappinga first portion of the tissue suture between the suture anchor and thebone. A second portion of the tissue suture, adjacent the first portionof the tissue suture, can be passed through an axial cannulation throughthe suture anchor prior to implanting the anchor into the bone. Thisaids in aligning the tissue suture along the suture anchor as it isimplanted to better trap the tissue suture. The second portion can bethreaded through the cannulation via a suture grasper passed through thecannulation by loading the second portion into a suture capturemechanism of the suture grasper located distal of the anchor and thenpulling the suture grasper, including the suture capture mechanism,proximally through the cannulation. Preferably, when the suture istrapped between the suture anchor and the bone, the soft tissue isdisposed on the tissue suture between the first portion and where thetissue suture connects to the collapsible loop.

In one aspect of the invention, the tissue suture is engaged at a distalend of the suture anchor prior to implanting the anchor into the bone.Preferably, the tissue suture is loaded into an eyelet located at thedistal end of the anchor.

Preferably, the collapsible loop is restrained via a post affixed to thesuture anchor and passing through the collapsible loop. Preferably, thecollapsible loop comprises a noose having a loop portion, a sliding knotclosing the loop portion and a post limb extending out of the slidingknot and thus the step of collapsing the collapsible loop comprisesapplying tension to the post limb. In one aspect of the invention, theanchor comprises a central axial cannulation with the loop portion andthe post limb extending proximally thereout and wherein the step ofcollapsing the loop draws the loop distally into the cannulation.

In one aspect of the invention, the tissue suture extends from the softtissue as a loop which interconnects with the collapsible loop and thusthe step of collapsing the collapsible loop tensions the loop of tissuesuture.

In one aspect of the invention, the anchor comprises a central axialcannulation with a fixed tail of the sliding knot and the post limbextending proximally thereout and wherein the fixed tail is passedthrough the soft tissue to become the tissue suture.

BRIEF DESCRIPTION OF THE DRAWINGS

In what follows, preferred embodiments of the invention are explained inmore detail with reference to the drawings, in which:

FIG. 1 is a perspective view of an adjustable anchor system according tothe present invention having a closed loop and an adjustable loop offilament;

FIGS. 1A, 2 and 3 are schematic cross-sectional views of alternativeanchor systems according to the present invention;

FIG. 4 is a schematic view of a closed loop after it has been pulledthrough a portion of tissue to be secured to bone, which may draw aportion of the adjustable loop with it through the tissue;

FIG. 5 illustrates an anchor being passed through the fixed loop anddirected toward a hole formed in the bone;

FIG. 6 shows the anchor fixated in bone with tension to be applied onthe post limb;

FIG. 7 illustrates the tissue in a desired position under final tensionafter the post limb has been trimmed;

FIG. 8 shows an alternative technique to that illustrated in FIGS. 6 and7 in which the anchor engages the closed loop instead of passing throughit;

FIGS. 8A-8C show yet other embodiments in which the closed loop has asufficient length to extend from the anchor up to and through thetissue, as illustrated in enlarged view in FIG. 8B, and another,less-preferred embodiment in which the closed loop has been eliminatedand the adjustable loop passes completely through tissue as illustratedin FIG. 8C;

FIG. 9 is a top plan view of a Tennessee Slider knot for use with sutureanchor systems according to the present invention;

FIG. 10 is a front elevation view in cross-section of a furtherembodiment of a suture anchor system according to the present invention;

FIG. 11A is a perspective view of the suture anchor body of the sutureanchor system of FIG. 10;

FIG. 11B is a top plan view of the suture anchor body of FIG. 11A;

FIG. 11C is a side elevation view of the suture anchor body of FIG. 11A;

FIG. 12 is a front elevation view in cross-section of a furtherembodiment of a suture anchor system according to the present invention;

FIGS. 13A to 13H are front elevation views in cross-section of a methodof using the suture anchor system of FIG. 12;

FIG. 14 is a front elevation view in cross-section of a furtherembodiment of a suture anchor system according to the present inventionhaving a distal eyelet;

FIGS. 15A to 15E are front elevation views in cross-section of a methodof using the suture anchor system of FIG. 14;

FIG. 16A is a front elevation view in cross-section of a furtherembodiment of a suture anchor system according to the present inventionhaving a distal eyelet and having a funnel shaped opening into theeyelet for loading suture into the eyelet;

FIG. 16B is a front elevation view in cross-section of a furtherembodiment of a suture anchor system according to the present inventionhaving a distal eyelet comprising overlapping arms for loading sutureinto the eyelet;

FIG. 16C is a front elevation view in cross-section of a furtherembodiment of a suture anchor system according to the present inventionhaving a forked distal tip for receiving suture;

FIG. 17 is a front elevation view in cross-section of a furtherembodiment of a suture anchor system according to the present inventionin which the sliding knot is proximal of the loop attachment to theanchor; and

FIGS. 18A to 18H are front elevation views in cross-section of a methodof using the suture anchor system of FIG. 17.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

This invention may be accomplished by an adjustable anchor system forsecuring tissue to bone, including an anchor having at least one passageextending from a proximal end toward a distal end. The passage defines arestriction such as a restricted opening or an occluding element. Theanchor has at least one bone-engaging feature disposed between theproximal and distal ends. The system further includes a first material,such as a first suture, formed as a closed, preferably fixed-length loopand capable of being placed through a portion of the tissue, and asecond filament having a terminal end, a post limb and a sliding knottied between the terminal end and the post limb to establish anelongated, adjustable-length loop which extends beyond the proximal endof the anchor and captures the closed loop of the first material. Theknot of the second filament is restrained by the restricted opening oroccluding element when tension is applied as desired to the post limb toshorten the elongated loop to draw the tissue toward the anchor until adesired tension is achieved.

Adjustable anchor system 10, FIG. 1, has a suture anchor 12, a closed,fixed-length loop 14 of a first material, and a second filament 16having a terminal end 18, a post limb 20, a sliding bunt line half hitchknot 22, and an adjustable loop 24 with loop limbs 26 and 28. In oneconstruction, suture anchor 12 is similar to the cannulated sutureanchor disclosed by Cauldwell et al. in U.S. Patent ApplicationPublication No. 2008/0147063, incorporated herein by reference. Inanchor systems according to the present invention, however, it is notnecessary to have a post-like suture-engaging member or other occludingelement over which one or more sutures or suture limbs pass to serve asa restriction to proximal movement; in many constructions, it issufficient to have a restricted opening 46 to prevent withdrawal of knot22 as discussed in more detail below, particularly in relation to FIGS.1A-3.

Suture anchor 12 has a proximal end 30 and a distal end 32 with opposeddistal arms 34 and 36 defining cut-out 38 between them. Passage 40 is aninner lumen which runs from proximal end 30 to distal cut-out 38.Although knot 22 is shown extending beyond cut-out 38 in FIG. 1 forpurposes of illustration, knot 22 preferably is seated againstrestricted opening 46 between arms 34 and 36, or otherwise maintained atthe distal end 32 by a cavity or other feature, during insertion ofanchor system 10 into a patient to minimize interference by the knot 22with the bone-engaging feature 42, or other exterior surface of anchor12, and the bone in which suture anchor 12 is fixated.

One or more bone-engaging features 42, such as the helical threadillustrated in FIG. 1 or other features such as teeth, ridges, or otherprotrusions, are formed on the exterior of anchor 12 to enhance fixationin bone. In one construction, the suture anchor rotates to toggle intobone at its proximal end to minimize withdrawal. In a number ofconstructions, a hole is formed in bone prior to anchor insertion; inother constructions, a suture anchor is inserted directly into bone.

One or more passages or channels may be formed on the exterior of thesuture anchor, such as channel 44 illustrated in phantom, FIG. 1,traversing bone-engaging element 42. Other configurations areillustrated in FIGS. 1A, 2 and 3 for adjustable anchor systems 10 a, 10b and 10 c, respectively, according to the present invention, havingfirst, fixed-length loops 14 a, 14 b, 14 c and second, adjustable lengthfilaments 16 a, 16 b, 16 c, respectively. Anchor 12 a, FIG. 1A, definesan inner lumen 40 a and an external passage 50 extending from the distalend to the proximal end of anchor 12 a. Sliding knot 22 a, formed insecond filament 16 a, is seated against restricted opening 46 a,adjustable loop 24 a extends through passage 40 a to capture closed loop14 a, and post limb 20 a lies within external channel 50 in thisconstruction.

It is a matter of surgeon preference whether a terminal end, such asterminal end 18 a, FIG. 1A, is kept at a length sufficient to lieagainst the exterior of at least one bone-engaging feature 42 a to betrapped against bone during insertion, or is trimmed to a shorterlength. Different examples of terminal end length are provided in FIGS.6-8 below. Further, a restriction such as restricted opening 46 a may bedefined at least in part by engagement with bone when anchor 12 a isfixated in bone to prevent knot 22 a from moving with post limb 20 awhen tension is applied to post limb 20 a as described in more detailbelow for procedures of using an anchor system according to the presentinvention.

Anchor system 10 b, FIG. 2, has at least three external passages orchannels 52, 54 and 56 without any internal passages in thisconstruction. Knot 22 b is maintained at the distal end of anchor 12 bby occlusion 51, defined at least in part by the distal surface ofanchor 12 b, while limbs 26 b, 28 b of loop 24 b lie within passages 52,54 and post limb 20 b of second filament 16 b lies within passage 56. Asdescribed above, occlusion 51 may be defined in part by engagement ofanchor 12 b with bone after fixation.

Anchor system 10 c, FIG. 3, has an internal passage 40 c through whichpost limb 20 c extends from a restricted opening 46 c which holds knot22 c. External passages 58, 60 carry limbs 26 c, 28 c of adjustable loop16 c. Although anchors 12 a, 12 b and 12 c are shown withoutdistal-extending arms in those constructions, in other constructions oneor more such distal extensions or other protrusions are provided,similar in some constructions to Cauldwell et al. cited above or to U.S.Pat. No. 7,381,213 by Lizardi, also incorporated herein by reference. Inyet other constructions, a cylindrical or otherwise circumferentialcavity, bowl or countersink feature is provided at the distal end of theanchor to seat the knot 22 during insertion and fixation.

In preferred constructions, loop 14, also referred to as a firstfilament, and second filament16 are formed of one or more types ofsutures. Acceptable diameters for second filament 16 include size 0 orsize 2 suture, such as Orthocord™ suture commercially available fromDePuy Mitek, while the same or larger diameters such as size 2 to size 5suture are preferred for loop 14, such as Ethibond™ suture availablefrom Ethicon. Orthocord™ suture is approximately fifty-five tosixty-five percent PDS™ polydioxanone, which is bioabsorbable, and theremaining percent ultra high molecular weight polyethylene, whileEthibond™ suture is primarily high strength polyester. In someconstructions, especially for shoulder repair procedures, loop 14 has afixed length of approximately one inch while adjustable loop 24 has alength of at least eighteen inches. The amount and type of bioabsorbablematerial, if any, utilized in the first or second filament is primarilya matter of surgeon preference for the particular surgical procedure tobe performed.

While the same type of suture can be used for both loop 14 and filament16, a suture having a lower abrasive property at its surface ispreferred for the first material forming closed loop 14. The lowerabrasive property can be achieved by a larger diameter, a softercomposition, a softer braid, plait or strand pattern, or a combinationof such characteristics. In some constructions, the suture material forclosed loop 14 is tied with a fixed knot to form the fixed-length loop14. In other constructions, loop 14 is molded or otherwise formed as aring of material.

Slidable knot 22 has been described as a bunt line half hitch knot insome constructions, but other suitable knots will be readily apparent tothose of ordinary skill in the suture tying art after reviewing thepresent invention. The term “slidable” as used herein is intended toinclude slidable, lockable knots as well as slidable knots. Severaltypes of suitable knots are described in the Arthroscopic Knot TyingManual (2005) available from DePuy Mitek, as well as in U.S. Pat. No.6,767,037 by Wenstrom, Jr.

One procedure according to the present invention for utilizing acannulated anchor system similar to that shown in FIG. 1 is illustratedin FIGS. 4-7 for attaching tissue 68 to bone 80. Reference numeralsutilized to describe the system shown for this procedure follow thenumerals utilized for system 10, FIG. 1, for simplicity and clarity,although a number of other types of anchors with different filament limbarrangements as illustrated in other Figures could also be utilized in asimilar manner. An initial suture 70, FIG. 4, having a needle 72 at itsdistal end is passed through tissue 68 to draw at least closed loop 14at least partially through tissue 68. Alternatively, a suture passinginstrument is inserted through tissue 68 to grasp the closed loop 14 andpull it through the tissue 68. The extent to which elongated, adjustableloop 24 is drawn through tissue 68, and whether an anchor passes throughor engages the closed loop 14 or adjustable loop 24, are described inmore detail below relative to FIGS. 8-8C.

In this procedure, a hole 82, FIG. 4, is formed through compact layer 84into cancellous layer 86 of bone 80 at a desired repair location. Anchor12, FIG. 5, is passed through an opening 89 in closed loop 14 asindicated by arrows 90 and is fixated in bone as shown in FIG. 6.Preferably, post limb 20 is extracted from the closed loop 14 afteranchor 12 passes through the opening 89 in closed loop 14, FIG. 5, sothat post limb 20 can pull directly one of adjustable loop limbs throughthe knot 22 without being constrained by closed loop 14. Terminal end 18is trapped between bone 86 and a portion of distal end 32 of anchor 12in this construction, and sliding knot 22 is held by a restrictedopening in internal lumen 40. Alternatively, terminal end 18 has asufficient length so that it extends proximally along the exterior ofthe anchor 12 past a plurality of bone engaging features 42 asillustrated in phantom as length 18 d, or is a shorter length 18 e asshown in FIG. 8.

After fixation of anchor 12, FIG. 6, proximal tension is applied to postlimb 20 as indicated by arrow 92. As post limb 20 is moved proximally,adjustable loop 24 readily slides through closed loop 14 as limbs 26 and28 are shortened. Tissue 68 is thereby drawn toward anchor 12 until afinal desired position, under desired tension, is achieved as shown inFIG. 7. Closed loop 14 engages the elongated loop 24 at first and secondlocations 96 and 98.

Other systems and methods according to the present invention are shownin FIGS. 8-8C as alternatives to the final configuration shown in FIG.7. Terminal end 18 e, FIG. 8, is intentionally short so that it is nottrapped between the anchor 12 and bone 80. In this construction,terminal end 18 e remains within the bone hole 82 and is not placedunder tension of any type.

Instead of requiring an opening 89, FIG. 5, in closed loop 14 to begreater than the circumference of the anchor 12 so that anchor 12 canpass completely through the closed loop 14, in other constructions thedistal end 32 engages a portion of the closed loop 14 as shown in FIG.8. Filament engagement can be accomplished such as shown in FIGS. 11 and12 of U.S. Pat. No. 7,381,213 by Lizardi. However, one benefit achievedby the present invention is that further tensioning of tissue 68 ispossible after anchor fixation by pulling on the post limb of theadjustable loop. Another benefit of the present invention is that theanchor inserter or driver and related driver instruments are removedprior to final tensioning and positioning of the tissue to be repairedto provide improved visual and tactile feedback to the surgeon.

Other arrangements of filaments are illustrated in FIGS. 8A-8C. Anchor12, FIG. 8A, engages filament portion 118 which passes through tissue 68to emerge at the other, proximal side in the circled region indicated at100. In the construction shown in FIG. 8B for that circled region 100,adjustable loop 124 passes through a portion of closed loop 114. Inother words, the same filament limbs form portions 114 and 118 of asingle closed, fixed-length loop. This arrangement is preferred becausethe limbs of adjustable loop 124 are able to slide over the closed loopfilament at location 116 without passing through tissue as adjustableloop 124 is reduced in size.

In contrast, limbs of adjustable portion 124 pass through tissue 68 inFIG. 8C, which represents an alternative configuration for FIG. 8A, andthe adjustable limbs emerge to form portion 118 which is engaged by thedistal end 32 of anchor 12. In other words, no closed loop is utilizedin the configuration represented by FIG. 8C. However, eliminating thefixed-length loop is less desirable because the adjustable loop may tendto lock on itself, and may bind with or cause damage to the soft tissuethrough which it passes. The adjustable loop may be prone to locking onitself even if the anchor is passed completely through the adjustableloop. Further, adjustability of portion 118, FIG. 8C, may be furtherimpeded by an interference fit with bone, unless the limbs of portion118 are properly aligned in channels or other exterior passages alonganchor 12.

A suture 200 for use with anchors according to the present invention canemploy a Tennessee Slider knot 202 (FIG. 9) in substitution for theblunt line half hitch knot 22. It comprises a loop 204, post limb 206and terminal end 208. The terminal end 208 passes over and then behindthe post limb 206, then over the loop 204, and then finally behind thepost limb 206 and back out.

FIGS. 10 and 11A to 11C illustrate a further embodiment of a sutureanchor 210 according to the present invention. It comprises a body 212having a proximal end 214 and distal end 216 with an axial lumen 218passing through the proximal end 214. The distal end 216 is slotted witha saddle 220 between two distal sides 222. An aperture 224 passesaxially through the saddle 220. Annular barbed flanges 225 about thebody 212 provide for enhanced fixation.

The suture 200 with the Tennessee Slider knot 202 is positioned in theanchor 210 with the knot 202 distal of the aperture 224 in a pocket 227created into the sides 222, a fixed tail 226 of the loop 204 passingproximally from the knot 202 through the aperture 224 and an adjustabletail 228 of the loop 204 wrapping around the saddle 220 to meet the knot202. The loop 204 extends proximally out of the lumen 218. The post limb206 extends proximally around the opposite side of the saddle 220 fromthe adjustable tail 228 and also extends proximally out of the lumen218. The anchor 210 can be employed in a fashion similar to theaforementioned embodiments.

FIGS. 12 and 13A to 13G illustrate an alternative procedure for use withsuture anchors according to the present invention. An anchor system 230comprises the suture anchor 210 with suture 200 rigged as illustrated inFIG. 10 and with a flexible wire suture capture device 232 having asuture capture loop 234 (such as a Chia Percpasser available from DePuyMitek, Inc. of Raynham, Mass.) threaded through the lumen 218 with thesuture capture loop 234 distal of the anchor body 212. A separate lengthof tissue suture 236 is threaded through the loop 204.

Typically the anchor system 230 is employed arthroscopically through acannula which would pass through a patient's skin 238 to the tissue 240and bone 242 where a repair is to be effected, but is not hereillustrated to better focus on the rigging and motion of the sutures 200and 236, and suture anchor 210. First a bone hole 244 is createdadjacent the tissue 240 (FIG. 13A). The tissue suture 236 is passedthrough the tissue 240 (such as a rotator cuff tendon) and pulled backout of the cannula (not shown) to be outside of the skin 238 (FIG. 13B)where it can be threaded through the suture capture loop 234 (FIG. 13C).A suture passer for passing suture through tissue such as the EXPRESSEWFlexible Suture Passer available from DePuy Mitek, Inc. of Raynham,Mass. can be employed for this. The suture capture device 232 is pulledproximally out of the lumen 218 threading the tissue suture 236 throughthe lumen 218 (FIG. 13D). The suture anchor 210 is then passed down thecannula (not shown) to the bone hole 244. The suture anchor distal end216 is placed into the hole 244 and slack is taken out of the tissuesuture 236 (FIG. 13E). The anchor 210 is then driven into the bone hole244 thus locking the tissue suture 236 between the anchor 210 and thebone 242 (FIG. 13F). Preferably the anchor 210 is inserted and driveninto the bone hole 244 via a cannulated driver 248 with the post limb206 situated within a cannulation 250 through the driver 248. After theanchor 210 is driven into the bone hole 244 the driver 248 is preferablyremoved (FIG. 13G) and then the post limb 206 is pulled to collapse theloop 204 and tension the tissue suture 236 (FIG. 13H).

Having the combination of the collapsible loop 204 and the tissue suture236 provides great advantage while collapsing the loop 204 duringtensioning of the repair. The loop 204 slides over the tissue suture 236rather than sliding through the tissue itself which allows for easiertensioning of the repair as the coefficient of friction between the loop204 and the tissue suture 236 will be less than if the loop 204 weresliding through the tissue itself and it minimizes any effects upon thetissue.

Although shown with a single anchor 210 a typical tissue repair mightinvolve a row of anchors or multiple rows of anchors. The anchor 210 andother embodiments are for instance useful with dual row rotator cuffrepairs in which a first medial row of anchors is placed beneath thecuff with suture therefrom extending up through the cuff and running toa second lateral row of anchors located near the edge of the cuff. Thesuture extending up through the cuff from the medial row could replacethe tissue suture 236 and be captured by anchors 210, in which case thesuture capture device would preferably rigged through the lumen 218 asin FIG. 10 and then back through the loop 204 so that it would pass thesuture from the medial anchors in place of the tissue suture 236. Tofacilitate loading such a loop of tissue suture the collapsing loopcould be rigged with a closed loop such as loop 14 with the anchor beingpassed therethrough and through the tissue suture loop so that thecollapsing loop rides against the closed loop as it collapses.

FIG. 14 illustrates a further embodiment of an anchor system 250according to the present invention. It comprises a suture anchor 252with suture 200 and a tissue suture 254. The anchor 252 comprises a body256 having a distal end 258 and proximal end 260. An axial lumen 262enters from the proximal end 260 and has a restriction 264 therein.Barbed flanges 266 encircle the body 256. An eyelet 268 is provided atthe distal end 258. The suture 200 is situated in the anchor with theknot 202 distal of the restriction 264 and the loop 204 and post limb206 passing proximally through the restriction 264 and out of the lumen262. The restriction 264 restrains the knot 202.

FIGS. 15A to 15E illustrate a procedure for the anchor system 250, andas in previous depictions the arthroscopy cannula and instrumentationare omitted for clarity. A bone hole 270 is formed in a bone 272 under apatient's skin 274 adjacent a tissue 276 (FIG. 15A). The tissue suture254 is passed through the tissue (FIG. 15B) and passed through theeyelet 268 (FIG. 15C). A suture capture device 232 (not shown in FIGS.15A TO 15E) could be employed through the eyelet 268 to ease loading thesuture 254 therethrough. The anchor 252 is placed at the bone hole 270,the slack is removed from the tissue suture 254 and then the anchor isdriven into the bone hole 270 to lock the tissue suture between theanchor 252 and the bone 272, preferably on two sides of the anchor 252.Tension applied to the post limb 206 collapses the loop 204 and tensionsthe tissue suture 254.

FIGS. 16A to 16C illustrate variations of the suture anchor system 250.Like parts in anchors 252 a, 252 b and 252 c have like part numbers tothe anchor 250 with the exception of their subscripts. Anchor 252 a(FIG. 16A) has an eyelet 280 having a funnel shaped slot 282 entrytherein for loading the tissue suture 254 a into the eyelet and theninhibiting its passage back out of the slot 282. Anchor 252 b (FIG. 16B)has an eyelet 284 formed of overlapping arms 286 creating a tortuouspath 288 into the eyelet 284 for the tissue suture 254 b. Anchor 252 c(FIG. 16C) has a fork tip 290 formed of distally projecting tines 292between which the tissue suture 254 c can be captured.

FIGS. 17 and 18A to 18H illustrate a further embodiment of a sutureanchor system 300 according to the present invention. It comprises asuture anchor 302 having an elongated cylindrical shape with an axialcannulation 304 and internal suture saddle 306. Annular barb-shapedflanges 308 encircle the anchor 302 to enhance its bone fixation. Asuture 310 comprise a sliding knot 312 forming a collapsing loop 314around the suture saddle 306 with a long fixed tail 316 and collapsingtail 318. A suture threader 320 comprises an elongated flexiblethreading wire 322 received through the cannulation 304 and terminatingin a distal suture capture loop 324 distal of the anchor 302.

To employ the suture anchor system 300, a bone hole 326 is formed in abone 328 beneath a patient's skin 330 and adjacent a soft tissue 332,such as for example a tendon, (FIG. 18A) which is to be attached to thebone 328 with the suture anchor system 300. The fixed tail 316 is passedthrough the soft tissue 332 and brought back outside of the skin 330(FIG. 18B). As in the prior procedure descriptions the procedure ispreferably performed arthroscopically and the associated arthroscopyequipment and the anchor driver are omitted from the FIGS. for clarityin illustrating the operation of the suture anchor system 300. The fixedtail 316 is loaded into the suture capture loop 324 (FIG. 18C) and thesuture threader 320 is withdrawn proximally through the cannulation 304to load the fixed tail 316 through the cannulation 304 (FIG. 18D). Thesuture anchor 302 is then placed into the opening of the bone hole 326and the slack is taken out of the fixed tail 316 (FIG. 18E). When thesuture anchor 302 is driven into the bone hole 326 it traps the fixedtail 316 between the anchor 302 and the bone 328 (FIG. 18F). By pullingon the collapsing tail 318 the collapsing knot 312 collapses the loop304 and moves down toward the suture saddle 306 thereby drawing fixedtail 316 and thereby the soft tissue 332 toward the anchor 302 (FIG.18G). The collapsing tail 318 and fixed tail 316 can then be trimmedcompleting the procedure (FIG. 18H). The resulting knot is very strongas tension between the fixed tail 316 where it leaves the knot 312 andthe loop 314 cinches the knot and such tension is provided by the loadbetween the soft tissue 332 and the suture saddle 306 thus providing astrong fixation.

The novel suture anchors of the present invention may be made from anumber of suitable materials including a metallic material, anon-biodegradable polymer, a biodegradable polymer, or a composite of abiodegradable polymer or copolymer and a bioceramic. The termbiodegradable as used herein is defined to mean materials that degradein the body and then are either absorbed into or excreted from the body.The term bioceramic as defined herein is defined to mean ceramic andglass materials that are compatible with body tissue. The bioceramicsare preferably biodegradable.

The metallic materials that can be used to manufacture the anchors ofthe present invention include stainless steel, titanium, alloys ofnickel and titanium, or other biocompatible metallic materials.

The non-biodegradable materials that can be used to manufacture theanchors of the present invention include polyethylene, polypropylene,PEEK (polyetheretherketone), or other biocompatible non-absorbablepolymers.

The biodegradable polymers that can be used to manufacture the anchorsused in the present invention include biodegradable polymers selectedfrom the group consisting of aliphatic polyesters, polyorthoesters,polyanhydrides, polycarbonates, polyurethanes, polyamides andpolyalkylene oxides. Preferably, the biodegradable polymers arealiphatic polyester polymers and copolymers, and blends thereof. Thealiphatic polyesters are typically synthesized in a ring openingpolymerization. Suitable monomers include but are not limited to lacticacid, lactide (including L-, D-, meso and D,L mixtures), glycolic acid,glycolide, .epsilon.-caprolactone, p-dioxanone (1,4-dioxan-2-one),trimethylene carbonate (1,3-dioxan-2-one), .delta.-valerolactone, andcombinations thereof.

The bioceramics that can be used in the composite anchors of the presentinvention include ceramics comprising mono-, di-, tri-, .alpha.-tri-,.beta.-tri-, and tetra-calcium phosphate, hydroxyapatite, calciumsulfates, calcium oxides, calcium carbonates, magnesium calciumphosphates. It is particularly preferred to use a .beta.-tritricalciumphosphate. In addition to bioceramics, bioglasses may also be used inthe composite screws. The bioglasses may include phosphate glasses andbioglasses.

Suitable biocompatible synthetic polymers can include polymers selectedfrom the group consisting of aliphatic polyesters, poly(amino acids),copoly(ether-esters), polyalkylene oxalates, polyamides, tyrosinederived polycarbonates, poly(iminocarbonates), polyorthoesters,polyoxaesters, polyamidoesters, polyoxaesters containing amine groups,poly(anhydrides), polyphosphazenes, polyurethanes, poly(etherurethanes), poly(ester urethanes), poly(propylene fumarate),poly(hydroxyalkanoate) and blends thereof.

For the purpose of this invention aliphatic polyesters include, but arenot limited to, homopolymers and copolymers of lactide (which includeslactic acid, D-,L- and meso lactide); glycolide (including glycolicacid); .epsilon.-caprolactone; p-dioxanone (1,4-dioxan-2-one);trimethylene carbonate (1,3-dioxan-2-one); alkyl derivatives oftrimethylene carbonate; .delta.-valerolactone; .beta.-butyrolactone;.gamma.-butyrolactone; .epsilon.-decalactone; hydroxybutyrate;hydroxyvalerate; 1,4-dioxepan-2-one (including its dimer1,5,8,12-tetraoxacyclotetradecane-7,14-dione); 1,5-dioxepan-2-one;6,6-dimethyl-1,4-dioxan-2-one; 2,5-diketomorpholine; pivalolactone;.alpha.,.alpha. diethylpropiolactone; ethylene carbonate; ethyleneoxalate; 3-methyl-1,4-dioxane-2,5-dione;3,3-diethyl-1,4-dioxan-2,5-dione-; 6,6-dimethyl-dioxepan-2-one;6,8-dioxabicycloctane-7-one and polymer blends thereof. Additionalexemplary polymer or polymer blends include, by non-limiting example, apolydioxanone, a polyhydroxybutyrate-co-hydrox-yvalerate,polyorthocarbonate, a polyaminocarbonate, and a polytrimethylenecarbonate. Aliphatic polyesters used in the present invention can behomopolymers or copolymers (random, block, segmented, tapered blocks,graft, triblock, etc.) having a linear, branched or star structure.Poly(iminocarbonates), for the purpose of this invention, are understoodto include those polymers as described by Kemnitzer and Kohn, in theHandbook of Biodegradable Polymers, edited by Domb, et. al., HardwoodAcademic Press, pp. 251-272 (1997). Copoly(ether-esters), for thepurpose of this invention, are understood to include thosecopolyester-ethers as described in the Journal of Biomaterials Research,Vol. 22, pages 993-1009, 1988 by Cohn and Younes, and in PolymerPreprints (ACS Division of Polymer Chemistry), Vol. 30(1), page 498,1989 by Cohn (e.g., PEO/PLA). Polyalkylene oxalates, for the purpose ofthis invention, include those described in U.S. Pat. Nos. 4,208,511;4,141,087; 4,130,639; 4,140,678; 4,105,034; and 4,205,399.Polyphosphazenes, co-, ter- and higher order mixed monomer basedpolymers made from L-lactide, D,L-lactide, lactic acid, glycolide,glycolic acid, para-dioxanone, trimethylene carbonate and E-caprolactonesuch as are described by Allcock in The Encyclopedia of Polymer Science,Vol. 13, pages 31-41, Wiley Intersciences, John Wiley & Sons, 1988 andby Vandorpe, et al in the Handbook of Biodegradable Polymers, edited byDomb, et al., Hardwood Academic Press, pp. 161-182 (1997).Polyanhydrides include those derived from diacids of the formHOOC—C.sub.6H.sub.4-O—(—CH.sub.2).sub.m-O—C.sub.6H.sub.4-COOH, where “m”is an integer in the range of from 2 to 8, and copolymers thereof withaliphatic alpha-omega diacids of up to 12 carbons. Polyoxaesters,polyoxaamides and polyoxaesters containing amines and/or amido groupsare described in one or more of the following U.S. Pat. Nos. 5,464,929;5,595,751; 5,597,579; 5,607,687; 5,618,552; 5,620,698; 5,645,850;5,648,088; 5,698,213; 5,700,583; and 5,859,150. Polyorthoesters such asthose described by Heller in Handbook of Biodegradable Polymers, editedby Domb, et al., Hardwood Academic Press, pp. 99-118 (1997).

Thus, while there have been shown, described, and pointed outfundamental novel features of the invention as applied to a preferredembodiment thereof, it will be understood that various omissions,substitutions, and changes in the form and details of the devicesillustrated, and in their operation, may be made by those skilled in theart without departing from the spirit and scope of the invention. Forexample, it is expressly intended that all combinations of thoseelements and/or steps that perform substantially the same function, insubstantially the same way, to achieve the same results be within thescope of the invention. Substitutions of elements from one describedembodiment to another are also fully intended and contemplated. It isalso to be understood that the drawings are not necessarily drawn toscale, but that they are merely conceptual in nature. It is theintention, therefore, to be limited only as indicated by the scope ofthe claims appended hereto.

Every issued patent, pending patent application, publication, journalarticle, book or any other reference cited herein is each incorporatedby reference in their entirety.

What is claimed is:
 1. A surgical filament snare assembly, comprising:an anchor capable of being fixated in bone and having a filamentengagement feature; a first filament having a noose with first andsecond noose limbs connected to the filament engagement feature of theanchor and emerging from the anchor as first and second free filamentlimbs which are capable of being passed through tissue to be repairedand then passable through the noose to enable incremental tensioning ofthe tissue after the anchor is fixated in bone, the noose strangulatingthe free filament limbs when tension is applied to at least one of thefree filament limbs and the noose; and a flexible sleeve joining atleast some portion of the first and second free filament limbs tofacilitate passing of the free filament limbs through tissue and thenthe noose as a single unit.
 2. The assembly of claim 1 wherein thesleeve is formed from a braided suture.
 3. The assembly of claim 1wherein the first filament is a braided suture and a section of one ofthe first and second free filament limbs serves as the sleeve.
 4. Theassembly of claim 3 wherein the sleeve section has fewer picks per unitlength than the picks per unit length for the remainder of the firstfilament.
 5. The assembly of claim 1 wherein the sleeve is positionedover the entire portion of the first and second free filament limbsbefore implantation of the anchor in a patient.
 6. The assembly of claim5 wherein the sleeve is further positioned beyond the filamentengagement feature to cover at least some of the first and second nooselimbs.
 7. The assembly of claim 1 wherein the noose is retractabletoward the anchor.
 8. The assembly of claim 1 wherein the noose isformed from at least one half hitch.
 9. The assembly of claim 1 furtherincluding at least one tube capable of being removably inserted into thenoose to provide a passage for the end of at least one of the freefilament limbs.
 10. A method of surgically repairing tissue, comprising:selecting an anchor capable of being fixated in bone and having afilament engagement feature; selecting a first filament having a noosewith first and second noose limbs connected to the filament engagementfeature of the anchor and emerging from the anchor as first and secondfree filament limbs which are capable of being passed through tissue tobe repaired and then passable through the noose, and a flexible sleevejoining at least some portion of the first and second free filamentlimbs to facilitate passing of the free filament limbs at least throughtissue as a single unit; fixating the anchor in bone; selecting at leastthe sleeve and passing it through the tissue to be repaired; passing atleast the free filament limbs through the noose; tensioning the tissueas desired after the anchor is fixated in bone, the noose strangulatingthe free filament limbs when tension is applied to at least one of thefree filament limbs and the noose; and removing the sleeve from thepatient.
 11. The method of claim 10 wherein the sleeve is formed from abraided suture.
 12. The method of claim 10 wherein the first filament isa braided suture and a section of one of the first and second freefilament limbs serves as the sleeve.
 13. The method of claim 12 whereinthe sleeve section has more than ten percent fewer picks per unit lengththan the picks per unit length for the remainder of the first filament.14. The method of claim 10 wherein the sleeve is positioned over theentire portion of the first and second free filament limbs beforeimplantation of the anchor in a patient.
 15. The method of claim 14wherein the sleeve is further positioned beyond the filament engagementfeature to cover at least some of the first and second noose limbs. 16.The method of claim 10 wherein passing the free filament limbs throughthe noose includes passing them with the sleeve as a single unit. 17.The method of claim 10 wherein the noose is retractable toward theanchor.
 18. The method of claim 10 wherein the noose is formed from atleast one half hitch.
 19. A surgical filament snare assembly,comprising: an anchor capable of being fixated in bone and having afilament engagement feature; a first filament having a fixed-lengthloop, capable of being passed through tissue and capable of being formedinto a noose, on a first portion of at least a first limb and having asecond portion; a second filament having a collapsible loop slidablyattached to the second portion of the first filament, the collapsibleloop being formed by a sliding knot with a tensioning limb, thetensioning limb and the sliding knot capable of being passed through thenoose to enable incremental tensioning of the tissue after the anchor isfixated in bone, the noose strangulating the collapsible loop whentension is applied to at least one of the free suture limb and thenoose; and at least one of the first filament and the second filamentslidably connected to the filament engagement feature of the anchor. 20.The snare assembly of claim 19 wherein the first filament is formed as acontinuous loop.
 21. The snare assembly of claim 19 wherein thecollapsible loop is slidably connected to the filament engagementfeature.
 22. A method of surgically repairing tissue, comprising:selecting an anchor capable of being fixated in bone and having afilament engagement feature; selecting a first filament having afixed-length loop, capable of being passed through tissue and capable ofbeing formed into a noose, on a first portion of at least a first limband having a second portion slidably attached to a collapsible loop of asecond filament, the collapsible loop being formed by a sliding knotwith a tensioning limb, the tensioning limb and the sliding knot capableof being passed through the noose; fixating the anchor in bone; passingat least a portion of the fixed-length loop through the tissue to berepaired; forming a portion of the fixed-length loop into a Lark's Headknot to serve as the noose; passing at the tensioning limb and slidingknot through the noose; and tensioning the tissue as desired after theanchor is fixated in bone, the noose strangulating the collapsible loopwhen tension is applied to at least one of the tensioning limb, thesliding knot, and the noose.
 23. The method of claim 22 wherein thefirst filament is formed as a continuous loop.
 24. The method of claim22 wherein the collapsible loop is slidably connected to the filamentengagement feature.
 25. A surgical filament snare assembly, comprising:an anchor capable of being fixated in bone and having a filamentengagement feature; and a first filament having a noose, formed from atleast one half hitch, on a first portion of at least a first limb andhaving a second portion connected to the filament engagement feature ofthe anchor, the noose capable of receiving at least two free filamentlimbs and strangulating them when tension is applied to at least one ofthe free filament limbs and the noose.
 26. The assembly of claim 25wherein the noose is retractable toward the anchor.
 27. The assembly ofclaim 25 further including a threader tool having at least twoprojections having distal ends capable of being removably inserted intodifferent loops of the half hitch, each projection defining a channelcapable of receiving a portion of at least one free filament limb topass it through a loop of the half hitch, and each projection furtherdefining a slot communicating with the channel to facilitate removal ofthe filament limb from the tool.
 28. The assembly of claim 27 whereinthe projections are tubes joined together with at least one handle formanipulating the tubes.
 29. The assembly of claim 27 wherein theproximal ends of the channels are connected by one of an intersectionand a common passage, and further including a stop as a proximal portionof the one of the intersection and the common passage.
 30. The assemblyof claim 29 wherein the stop is movable to assist removal of thefilament limbs from the tool.
 31. The assembly of claim 30 furtherincluding a spring to bias the stop toward the one of the intersectionand the passage.
 32. The assembly of claim 27 further including at leasttwo suture passers having distal ends for engaging portions of the freefilament limbs, and the suture passers capable of pulling the freefilament limbs through the channels when proximal-directed force isapplied to proximal ends of the suture passers.
 33. The assembly ofclaim 32 wherein the distal ends of the suture passers are intertwinedin at least one half hitch to impart at least one half hitch to the freefilament limbs when they are drawn through the tool.
 34. The assembly ofclaim 25 wherein the noose has been formed by passing at least two endsof the first filament through a central opening of the half hitch tocreate the noose.
 35. A method of creating a surgical filament snareassembly, comprising: selecting an anchor capable of being fixated inbone and having a filament engagement feature; selecting a firstfilament having first and second ends; forming at least one half hitchwith a central opening in the first filament between the first andsecond ends; passing the first and second ends through the centralopening to define a noose with first and second noose limbs; tighteningthe half hitch to form a slidable knot for the noose; and passing thefirst and second filament ends through the filament engagement featureof the anchor to emerge from the anchor as first and second freefilament limbs which are capable of being passed through tissue to berepaired and then passable through the noose, the noose strangulatingthe free filament limbs when tension is applied to at least one of thefree filament limbs and the noose opening.
 36. The method of claim 35further including adding a flexible sleeve joining at least some portionof the first and second free filament limbs to facilitate passing of thefree filament limbs at least through tissue as a single unit.
 37. Themethod of claim 36 wherein the first filament is a braided suture and asection of one of the first and second free filament limbs serves as thesleeve.